Basically, all Mako ever wanted was to try and make her family happy, especially her father who is similarly respected by every member of his family. It's a very rural Japan, particularity farming family, trope. But at the deepest part of her heart, Mako wants to break free and be her own woman, which is why all the omiai/dates end up failing. Satou is the only one to see that conflict (or the only one to care) and he makes the difficult decision to break away. Maybe he's too idealistic or maybe he sees what the future may bring where he may get himself hurt, but he decides to break off the relationship. And this devastated Mako because this one was perhaps the first one she felt was the one she could love, she might even love. But a girls got her pride, and the situation at home ever drives her forward to the next omiai prospect.
Satou on his part, can't completely leave. If he can't have romantic love, he wants to be a person who can still bring about her happiness, if only in a roundabout way. I know there's criticism about him being wimpy and ask that, and that's actually pretty fair. The ending will make that fairly clear. But he is agitating for a change in Mako's family for her happiness, and that will bear fruit.
Can't go into any real details because spoilers but it is a worthwhile journey. I loved it. Incidentally, this was the manga that got me to start collecting manga again. Back in April, I got so curious about the ending, I purchased the set and read through. Since then, I bought a ton of manga and even started scanlating.